Precipitator3 Data Sections
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Precipitation3  Model Theory  Growth  Model Theory  PSD  Model Options  Data Sections  Dynamic Mode  Batch Operations (Probal) 

Latest SysCAD Version: 31 May 2024  SysCAD 9.3 Build 139.35544
Related Links: Alumina 3 Bayer Species Model
Precipitator3 Tab
Unit Type: Precipitator3  The first tab page in the access window will have this name.
Tag (Long/Short)  Input / Calc  Description/Calculated Variables / Options 
Tag  Display  This name tag may be modified with the change tag option. 
Condition  Display  OK if no errors/warnings, otherwise lists errors/warnings. 
ConditionCount  Display  The current number of errors/warnings. If condition is OK, returns 0. 
GeneralDescription / GenDesc  Display  This is an automatically generated description for the unit. If the user has entered text in the 'EqpDesc' field on the Info tab (see below), this will be displayed here. If this field is blank, then SysCAD will display the UnitType or SubClass. 
Requirements  
On  Tick Box  This can be used to take a precipitator off line. When a precipitator is not ON, the input stream will act as though it has bypassed the precipitator, thus no change will occur in this unit. This option is useful for feasibility studies of flowsheet configuration. 
TankBypass  Tick box  Feed bypasses entirely to Product, tank contents continue to react. Dynamic only 
Bypass  Tick box  Allows bypassing of a fraction of feed directly to outlet. Bypassing for more information. In Dynamic mode, this represents shortcircuiting of feed to product, so will only occur while the tank is overflowing, else all feed is added to tank contents. 
BypassFraction  Input  How much of the feed to bypass, visible if Bypass is on. 
TankVol  Input  The precipitation tank volume, used to calculate the residence time. 
LevelControl  Tick Box  Enable tank level control. Dynamic only with Underflow connection. 
Level.Spt  Input  Target level for level control. Dynamic only with LevelControl enabled. 
Level.QvMin  Tick Box  Minimum underflow flowrate for level control. Dynamic only with LevelControl enabled. Default 0. 
Level.QvMax  Tick Box  Maximum underflow flowrate for level control. Dynamic only with LevelControl enabled. Default '*' (unrestricted). 
BatchMode  Tick Box  Adds the Batch & Cycle tabs. The precipitator model will operate in a pseudodynamic batch mode, simulating a tank which is filled with separate feed and seed streams, allowed to precipitate, then drained. See Batch Mode for more information.\\ 
EnthalpyCalcs  Original (Hz)  Original option for compatibility with older projects. To be deprecated. 
Managed HOR (Hs)  UserSpecified Reaction Heats.
 
Species DB HOR (Hf)  Reaction Heats Determined from Species Data H25.  
Cooling  None  No cooling required. 
Embedded  Uses embedded cooler for cooling. User do not need to add the cooler unit. A Cooler Tab becomes visible and can be configured. See also Cooler Options for more information.  
External  Uses external cooler for cooling. User will need to add the cooler unit separately. A Cooler Tab tab becomes visible and can be configured. See also Cooler Options for more information.  
Reactions  Off  No extra reactions 
On  This allows the user to add extra reactions to the model. Note that THA precipitation and Soda coprecipitation are builtin reactions, user do not need to specify these. When this option is on, RB becomes visible and may be configured. See Reactions for more information.  
Classification  Tick Box  Only relevant if unit has an Underflow connection (from Build 139, the Classification option does not appear unless this is connected) Adds the Classif tab. Allows Solid and liquid separation using an internal General Separator model. See Classification for more information. 
ThermalOverride  None  Don't override. 
TempDrop  Overall heat loss based on Temperature Drop. Note that calculated HOR and cooling effects are ignored as this temperature drop is applied as an overall override.  
ProductT  Specify the product temperature.  
TempDropReqd / TDropReqd  Input  The overall temperature drop required, visible with the TempDrop ThermalOverride Method. 
TemperatureReqd / T_Reqd  Input  The overall exit temperature required, visible with the ProductT ThermalOverride Method. 
ThermalLossMethod (Only visible if the ThermalOverride is set to NONE.) 
None  No additional heat loss to the environment or thermal balance overrides. 
TempDrop  Additional heat loss based on Temperature Drop. In this case the temperature drop is applied on top of HOR and cooling effects.  
FixedLoss  Additional heat loss is expressed as a fixed amount of energy.  
Ambient  Additional heat loss is expressed as Energy/degree of temperature difference to ambient.  
WindAmbient  More detailed ambient model accounting for wind speed. See Thermal Loss Method for equation and limits.  
WindAmbient2  More detailed ambient model accounting for wind speed. See Thermal Loss Method for equation and limits.  
TempDropReqd / TDropReqd  Input  The temperature drop required (for energy loss not necessarily the overall tank temperature drop), visible with the TempDrop Method. 
ThermalLossReqd  Input  The amount of energy to be lost to the environment, visible with the FixedLoss method. (Positive for heat outflow) 
ThermalLossAmbient  Input  The amount of energy per degree to be lost to the environment, visible with the Ambient method. 
LocalWindSpeed  Tickbox  Visible with the WindAmbient ThermoLossMethod. Selecting this option allows user to use a local wind speed, this could be different than that specified in the Plant Model  Environment tab. If it is not selected, then the value specified in the Plant Model  Environment will be used. 
WindSpeedUsed  Result  Displays the actual wind speed used. 
WindLossRateK  Input  Rate, visible if WindAmbient option for thermal loss is selected. 
TankSurfaceArea  Input  Tank external surface area including both top and side, visible if WindAmbient option for thermal loss is selected. 
LocalAmbientT  Check Box  Allow individual tank specification of ambient temperature. If off, PlantModel.Environment.T is used. 
AmbientT.Reqd  Input  Local ambient temperature for thermal loss and evaporation calculations using Ambient. Visible if LocalAmbientT is enabled. 
Evaporation  None  No evaporation loss to the environment. 
Fixed  Fixed evaporation rate. Suggested values are in the range 0.25 to 1.0 t/h.  
Ambient  Fixed evaporation rate per degree of temperature. Suggested values are in the range of 0.005 to 0.025 t/h.K.  
Evap.Rate  Input  The evaporation rate required, visible with the Fixed Method. 
Evap.Per.degK  Input  The evaporation rate required per degree of temperature, visible with the Ambient method, or overall constant for detailed model. 
ProdGasEntrainment  Input  The fraction of vapours which report to the Product stream rather than the Vent. This includes any vapours from the feed stream or gases evolved from reactions. This excludes water from evaporation. Default 0%. 
OperatingP  NOTE: this pressure is applied to the (combined) feed, before submodels (if any).  
Method  AutoDetect  If there are any liquids AND no vapours present in the feed, outlet streams will take the highest pressure of the feeds. Else (e.g. some vapours present) outlet streams will take the lowest pressure of the feeds. 
LowestFeed  Outlet streams will take the lowest pressure of the feeds.  
HighestFeed  Outlet streams will take the highest pressure of the feeds.  
Atmospheric  Outlet streams will be at Atmospheric Pressure. The atmospheric pressure is calculated by SysCAD based on the user defined elevation (default elevation is at sea level = 101.325 kPa). The elevation can be changed on the Environment tab page of the Plant Model.  
RequiredP  Outlet streams will be at the user specified pressure.  
IgnoreLowMassFlow / IgnoreLowQm  Tick Box  This option is only visible if the AutoDetect, LowestFeed or HighestFeed methods are chosen. When calculating the outlet pressure and temperature of the tank, SysCAD will ignore the low flow feed streams should this option be selected. The low flow limit is set in the field below. 
LowMassFlowFrac / LowQmFrac  Input  This field is only visible if the IgnoreLowQm option is selected. This is the amount any stream contributes to the total flow. For example, if the total feed to the tank is 10 kg/s, and this field is set to 1%. Then any feed streams with less than 0.1 kg/s will be ignored in the pressure calculations. 
PressureReqd / P_Reqd  Input  This field is only visible if the RequiredP method is chosen. This is user specified pressure. 
Result  Calc  The actual pressure used for the sum of the feeds which will also be the outlet pressure (unless further model options change the pressure). 
PresetData(Dynamic Only)  
UsePresetImg  Tickbox  Selecting this option will add the Preset + DSp Tabs, allowing user to define a premade mixture to be used to preset the contents of the precipitator. 
Temperature / T  Input  User specified preset Temperature, used when the preset tank command is executed. 
Level / T  Input  User specified preset level, used when the preset tank command is executed. 
Options  
ShowQFeed  Tick box  Switches on the QFeed tab pages to display the total feed stream properties into the Precipitator. This is useful if more than one Feed streams are connected to the precipitator. See Material Flow Section. 
ShowQTank  Tick box  Visible if Bypass is on. Switches on the QTank tab pages to display the tank contents exit stream properties before adding the bypass to give the exit stream (QProd). See Material Flow Section. 
ShowQEvap  Tick box  Visible if Evaporation method selected. Switches on the QEvap tab pages to display stream details of the evaporated water. See Material Flow Section. 
ShowQVent  Tick box  Visible with Vent connection. Switches on the QVent tab pages to display the vent stream properties from the Precipitator. This may include water vapour from evaporation. See Material Flow Section. 
ShowQProd  Tick box  Switches on the QProd tab pages to display the product stream properties from the Precipitator. This may include vent gases if no Vent stream connected. See Material Flow Section. 
ShowQTubeIn  Tick box  Visible if embedded cooling. Switches on the QTubeIn tab pages to display cooling tubes inlet stream properties. See Material Flow Section. 
ShowQTubeOut  Tick box  Visible if embedded cooling. Switches on the QTubeOut tab pages to display cooling tubes outlet stream properties. See Material Flow Section. 
Results Tank  
ResidenceTime  Calc  The calculated residence time of the slurry in the unit. 
TotalMass / Mt  Calc  The total mass of the slurry in the unit. 
SolidMass / SMt  Calc  The mass of the solid in the unit. 
Eff.ResidenceTime  Calc  Effective solids residence time from Classification. Note: when classification is used, solids have a longer residence time due to internal recycle. 
Level  Calc  Tank level as fraction of volume. Dynamic Only 
QmAcc  Calc  Nett inflow rate Dynamic Only 
MtAcc  Calc  Nett inflow Dynamic Only 
SSN_Ratio / SuperSat  Calc  The Supersaturation = Product A/C divided by Equilibrium A/C = (A/C) / (ASat / C@25). This is the same as the ratio of A to ASat. A and C are referenced to 25°C. 
Solids.Conc  Calc  The solids concentration in the unit referenced to 25°C. 
Yield(in grams Al_{2}O_{3} per liter liquor @ 25C)  
Yield  Calc  The calculated Yield = Gibbsite precipitated as equivalent Alumina per unit volume of feed liqour at 25°C. Note: in Dynamic, this is the difference in THA between feed and product streams, and may be negative or meaningless if tank is filling or in batch operation. 
YieldRate  Calc  Rate of increase in THA solids (gpl/hr) Dynamic Only 
THA.Precip  Calc  The mass of Trihydrate Alumina Al[OH]_{3} precipitated in the unit. 
Al2O3.Precip  Calc  The mass of Trihydrate Alumina Al[OH]_{3} precipitated in the unit, expressed as Al_{2}O_{3}. 
Solids.Precip  Calc  The mass of solids precipitated in the unit, includes THA, bound soda and bound organics. 
Oxalate(Only visible if the oxalate precipitation is on.)  
Oxalate.Precip  Calc  The mass of oxalate precipitated in the unit. 
Oxalate.Yield  Calc  The mass yield of oxalate in the tank (g Na2C2O4 / L liquor). Only shown in Steady State. 
Oxalate.Solubility  Calc  The oxalate solubility at equilibrium (g Na2C2O4 / L). 
Oxalate.SSN  Calc  The oxalate relative super saturation level (Ox / Ox*  1). 
Results  
MassFlowIn / Qmi  Calc  The mass flowrate at the inlet conditions. 
MassFlowOut / Qmo  Calc  The mass flowrate at the Product Stream. Note: If the classification option is on, this shows the classifier overflow (product) flowrate. The underflow flowrate is shown under the Results Underflow section. 
MassFlowLoss / QmLoss  Calc  This shows the mass flow difference between inlet and outlet streams. If vapour is present (due to reactions or evaporation) and the vent stream is not connected, then the vapour will be discarded, the mass imbalance value will be shown here. 
VolFlowIn / Qvi  Calc  The volumetric flowrate at the inlet conditions. 
VolFlowOut / Qvo  Calc  The volumetric flowrate at the outlet conditions. 
BypassQm  Calc  The mass flowrate of the bypass material. 
BypassQv  Calc  The volumetric flowrate of the bypass material. 
TemperatureIn / Ti  Calc  The inlet temperature. 
TemperatureOut To  Calc  The outlet Temperature. 
ACin  Calc  The A/C ratio at the inlet conditions. 
ACout  Calc  The A/C ratio at the outlet conditions. 
ACequil / ACSat  Calc  The A saturation at the outlet conditions to C concentration at 25 °C. 
BoundSodaFraction  Calc  (The bound soda and bound organics precipitation rate expressed as Na_{2}O) / (THA precipitation rate expressed as Al_{2}O_{3}). 
BoundSodaPrecip  Calc  The bound soda precipitation rate. If NaOH*(s) is present in the project, this will show the bound soda as NaOH, otherwise this will show bound soda expressed as Na_{2}O.

BoundSodaPerTHA  Calc  (The bound soda precipitation rate expressed as "boundsodaspecies") / (THA precipitation rate expressed as Al[OH]_{3}).

BoundOrganicsPrecip  Calc  The bound organic precipitation rate  expressed as the bound organic species, such as Na_{2}C_{5}O_{7}*(s).

Results UnderflowOnly visible with Classification option selected.  
UF.MassFlow / UF.Qm  Calc  The mass flow of the underflow stream. 
UF.SolidMassFlow / UF.SQm  Calc  The solid mass flow of the underflow stream. 
UF.SolidFrac / UF.Sf  Calc  The solid mass fraction of the underflow stream. 
UF.VolFlowOut / UF.Qv  Calc  The volumetric flow of the underflow stream. 
Precip Tab
Tag (Long/Short)  Input / Calc  Description/Calculated Variables / Options 
Precip.On  Tickbox  Enable precipitation chemistry functionality. Dynamic only 
Precip.Method  SSA  Uses the specified seed surface area estimated from the input stream conditions. User can specify a SSA value by ticking the OverrideSSA option. NOTE: If there is a PSD in the feed, it will be removed from the outlet stream. 
PSD  Use the Full Particle Size Distribution (PSD). Refer to Alumina3 Precip  Full PSD for more information.  
Hydrate Precipitation  
GrowthMethod  Fixed  User specifies a fixed alumina precipitation rate (as a mass flow rate). 
FixedRate  The alumina precipitation rate is calculated from a fixed user specified growth rate.  
WhiteBateman  The alumina precipitation rate is calculated using the White Bateman correlations [2]. See Growth Rate Theory for information.  
VeeslerBoistelle  The alumina precipitation rate is calculated using the Veesler Boistelle correlations [7]. See Growth Rate Theory for information.  
SSA Yield  The alumina precipitation rate is calculated taking into account factors of free caustic, total organic carbon, soda concentration and SSA. See Growth Rate Theory for information.  
GrowthAsDeposition  Input  Removed in Build 139. Defines growth rate as radial/crystal growth (true) or diametric/particle growth (false). 
UseCorrectedGrowthRate  Input  Available from Build 139. (May be visible if upgrading project.) Removes GrowthAsDeposition option  radial and diametric growth are both calculated and applied as required by different growth and agglomeration methods. Recommend this box be checked and model retuned if necessary. 
GrowthRateCorr  Input  Growth rate correction factor, applied to all methods except Fixed. 
VolumeCorrection  Tickbox  Reduces precipitation rate for alumina and bound soda to account for excess volume in Dynamic calculation step. May be useful for large time steps. Default off. Dynamic only 
SeedSSA  Tickbox  Visible with Precip.Method set to SSA. If aluminate is available but no solid THA is present, this will seed a small arbitrary mass of THA and creates the SSA quality at 0.050 m^2/g. This can assist with startup from reset. 
OverrideSSA  Tickbox  Visible with Precip.Method set to SSA. Allows user to specify a SSA value for the precipitation tank. Any feed stream value will be ignored. 
AdjustProdSSA  Tickbox  Adjust product stream SSA to account for particle growth (using spherical model).

UserFeedSSA / SSA  Input  The seed surface area specified directly by the user. Any SSA value, if present, in the feed stream is ignored. Visible when Precip.Method is SSA. 
SSAin  Calc  The current SSA value from feed stream. 
SSAUsed  Calc  The SSA value used in the calculations as per the above inputs. 
THA.Density  Calc  The THA species solids density (used in GrowthRate calculation). 
Variables for the Fixed GrowthMethod  
Precip.Rate  Input  The user specified precipitation rate. 
Variables for the FixedRate GrowthMethod  
FixedGrowthRate  Input  The user specified growth rate. 
Variables for the WhiteBateman GrowthMethod  
ER_White  Input  The Activation Energy (E) divided by the Gas Constant (R), in units Kelvin. 
K_White  Input  The Constant used in the Growth Rate Factor correlation. 
gF_White  Input  This allows the user to tune the growth rate based on a factor. 
Variables for the VeeslerBoistelle GrowthMethod  
ER_VB  Input  The Activation Energy (E) divided by the Gas Constant (R), in units Kelvin. 
K_VB  Input  Overall growth rate constant. 
Beta.Critical  Input  Critical supersaturation (nominally 1), must be exceeded for growth to occur 
N_VB  Input  Exponent g for relative supersaturation term [math]\displaystyle{ (\beta\beta_c)^g }[/math] 
Variables for the SSA Yield GrowthMethod  
ActivationEnergy/R  Input  The Activation Energy (E) divided by the Gas Constant (R), in units Kelvin. 
K0  Input  The Constant used in the Growth Rate Factor correlation. Default value for K_0 is 2.2*10^{11}. This value is typically tuned for plant conditions. It may need adjustment as additional terms described below are adjusted. 
n_TOC  Input  Organics term = [math]\displaystyle{ e^{n_{TOC} \quad \times \; TOC} }[/math]. Using zero for n_TOC will remove TOC dependence. 
n_s  Input  Total Soda effect = S^{n_s}. Using zero for n_s will remove the precipitation dependence on soda. 
n_fc  Input  Free Caustic – Free caustic is the sodium hydroxide in solution that is not associated with dissolved alumina. KFreeCaustic = FC^{n_fc}.Using zero for n_fc will remove the precipitation dependence on free caustic. 
n_C  Input  Additional Caustic effect term C^{n_C}. The default value is zero. 
n_AC  Input  This is the n factor for the supersaturation driving force term. [math]\displaystyle{ \left( \frac{A_{out}  A^*}{C} \right)^n }[/math]. The default value is 2. 
n_ssa  Input  Specific Surface Area, SSA. This correction accounts for the fact that the effective surface area for precipitation may not scale linearly with SSA. Kssa = SSA^{nssa}. The default value for n_{ssa} is 1.0 (making precipitation rates linearly proportional to SSA). 
GrowthMethod Results  
kG  Calc  kG constant for the GrowthMethod 
GrowthRateFactor  Calc  Product of kG and [math]\displaystyle{ e^{E/RT} }[/math] 
GrowthRateR  Calc  Radial (i.e. crystal) growth rate. This is the growth rate term multiplied against particle surface area to determine precipitation rate. See Growth Rate Methods for more details. 
GrowthRateD  Calc  Diametric (i.e. particle) growth rate. GrowthRateD = 2 x GrowthRateR 
Precip Heat of Reaction  
UserHOR  Tickbox  Option for User to enter Heat of Reaction for Gibbsite Precipitation reaction (kJ/kgGibbsite). The default value is 252.3 kJ/kgGibbsite at 0°C. NB this is an exothermic reaction and energy is released as Gibbsite precipitates. For reference, please refer to Heat of Dissolution of Gibbsite and Boehmite 
User.GibbsiteHOR@0C  Input  The Gibbsite precipitation HOR value to be used. Only available when UserHOR is selected. NB a positive entry generates a warning message as the HOR shold be negative. For reference, please refer to Heat of Dissolution of Gibbsite and Boehmite 
GibbsiteHOR@0C  Calc  The Gibbsite precipitation HOR value used. 252.3 kJ/kgGibbsite at 0°C if UserHOR is not selected. For reference, please refer to Heat of Dissolution of Gibbsite and Boehmite 
AluminaHORMethod  Input  Different Methods for specifying Alumina Heat of Reaction (New) 
Bound Soda Calculations  
BoundSodaMethod (Not visible with Fixed GrowthMethod) 
Ohkawa  Ohkawa, Tsuneizumi and Hirao [5] method with corrections for bound soda as Na2O and NaOH*  now the default method. See Bound Soda Theory for information. 
Hunter  Armstrong, Hunter, McCormick and Warren. [6] correlation, see Bound Soda Theory for information.  
Fixed %  Calculates a fixed percentage of soda coprecipitation with the precipitated hydrate. This specifies soda as NaOH as a mass fraction of alumina as THA.  
K_tuneBS  Input  The tuning factor for the bound soda calculation. 
K1  Input  The soda factor. The default value is 1.27*10^{3}. 
E_SODA  Input  Constant used in the bound soda calculation, default is 2535 K^{1} 
BoundSodaFrac  Input  Visible when BoundSodaMethod is set to Fixed. The user specified bound soda fraction. 
BoundSodaSpecies  Text  Display the bound soda species used for occlusion. If NaOH* is present, it will be used, if not, the project will use Na2O. If neither is present, the project will force add Na2O(s) to the species list. 
BoundSoda_OrgPart  Input  The percentage of bound soda precipitated as organics. If the bound organic species is not present in the project, a warning message: Organics precipitation and BoundSoda_OrgPart not available:Matching bound organic solid for Na2C5O7(aq) not found will be given. See Bound organics for more information. 
Oxalate Calculations  
OxalatePrecip  None  No oxalate coprecipitation occurs. 
Fixed  Oxalate coprecipitation will occur at a user specified fixed rate.  
Supersaturation  The oxalate supersaturation form uses a driving rate proportional to the square of the oxalate supersaturation above an optional metastable value. Please note that this is only a made up equation with no theory or experimental data to support it. It is added here so the precipitation can be varied based on the tank conditions. For users with their own correlation data, it will be highly recommended to calculate the rate using general controller or MP file, then set the oxalate precipitation rate using the Fixed Method. See Oxalate Precipitation Theory for more information.  
McKinnon  McKinnon, Parkinson and Beckham [8] equation, see Oxalate Precipitation Theory for information.  
OxalateReqd  Input  Visible with OxalatePrecip set to Fixed. User defines the amount of oxalate precipitation as a fixed amount. If user correlation is available, the oxalate precipitation can be calculated in a PGM or MP file using the correlation, then set the calculated rate here. 
OxSSatReqd  Input  Oxalate supersaturation fraction (Ox / Ox*  1) required for oxalate precipitation, used to account for metastability. Used by the Supersaturation method. 
OxSSatK  Input  Constant used by the Supersaturation oxalate precipitation method. 
OxalateRateFactor  Input  Oxalate precipitation rate tuning factor used by the McKinnon method. 
Solution Convergence(Not visible if using Batch Mode)  
UseLastConverged  Tickbox  If selected, will restart solution iteration at last converged state. If the solution is nearly converged, this will speed up the iteration. If the solution was converged, and nothing else is changed it should immediately converge. 
Convergence.Limit  Input  Global tolerance for testing convergence for iterative calculation in all precipitator tanks. Default is 1.0e8. 
Thermal.Damping  Input  Damping for energy convergence. Default of 0. 
Mass.Damping  Input  Damping for mass convergence. Default of 0. This value may need to be increased, often significantly 80% plus, for a precip tank with a significant change. Try increasing this when failed to converge error message is shown. 
Ext.FlowDamping  Input  Damping for external cooling volume flow convergence when using external cooling. Default of 0. 
ClassifierError  Tickbox  Include classifier recycle in overall convergence 
NumberErrors  Tickbox  Include PSD numbers in overall convergence 
PSDErrScale  Input  Relative Contribution of PSD Error 
MinIterations  Input  Minimum number of iterations for the convergence loop. 
MaxIterations  Input  Maximum number of iterations for the convergence loop. 
Iterations  Calc  Number of iterations solved. 
Yield Error  Calc  Error in convergence of yield calculations 
PSDError  Calc  Error in convergence of particle numbers. 
ClassifyError  Calc  Error in convergence of classifier recycle. 
TotalError  Calc  Total Error. 
Dynamic Time Step(Options for additional internal iterations at smaller time steps for dynamic calculation. Allows for higher precision precipitation in projects with large step sizes. Note: This may cause increased project solve time. Dynamic Only)  
Safety.TimeStep  Iteration Count  Use a specified number of internal time steps. E.g. if the Dynamic Solver Step Size is 300s and IntegrationSteps = 5, then 5 internal time steps of 60s each will be used. 
Max Time Step  Use a specified maximum internal time step. The number of internal iterations will depend on the Dynamic Solver Step Size. Input value is local to the tank. E.g if the project time step is 300s and MaxTimeStep = 120s, then 3 internal time steps of 100s each will be used.  
Max Time Step Global  As with Max Time Step but the input value is global.  
IntegrationSteps  Input  Input for Iteration Count. 
MaxTimeStep  Input  Local input for Max Time Step. 
Global.MaxTimeStep  Input  Global input for Max Time Step Global. 
IntegrationStepsUsed  Calc  The number of internal time steps used. Visible with MaxTimeStep or Global.MaxTimeStep. 
Thermal and Mass Balance  
Env.Thermal.Loss  Calc  The amount of energy lost to the environment. 
Evap.Mass.Loss  Calc  The evaporation mass rate 
Evap.Thermal.Loss  Calc  The amount of energy lost through evaporation. 
Batch.Evap (only visible if both the BatchMode and Evaporation options are ON)  
Feed.Evap.T  Calc  the PGL feed temperature after evaporation (only visible if both the BatchMode and Evaporation options are ON) 
Feed.Evap.DeltaT  Calc  the temperature drop in the feed stream (only visible if both the BatchMode and Evaporation options are ON) 
Cooler.Thermal.Loss  Calc  The amount of energy transferred through the cooler. 
Total.Thermal.Loss  Calc  Total amount of energy loss: Evap + Env + Cooler. 
ReactionHeat@0  Calc  The amount of energy released by the precipitation reaction at the 0dC temperature. 
ReactionHeat(@T)  Calc  The amount of energy released by the precipitation reaction at the product temperature. 
Stream Enthalpy  
HzIn  Calc  Enthalpy flux into Precipitator. 
HzEvap  Calc  Enthalpy flux to Evaporation. 
HzOut  Calc  Enthalpy flux of the product stream. If classifier option is being used, then this will only show the overflow stream, the underflow stream will be shown in UF.HzOut. 
UF.HzOut  Calc  Enthalpy flux of the underflow stream. Only visible if classifier option is being used. 
HzBal  Calc  Enthalpy out minus enthalpy in. This is the net of heat transfer, evaporation loss and reaction heat (NB Rxn heat measured at 0°C reference temperature). 
FeedHf  Calc  The total energy of the feed. 
ProdHf  Calc  The total energy of the product. 
EvapHf  Calc  The total energy of the material evaporated from the precipatator, if evaporation is used. 
Cooler Tab
Tag (Long/Short)  Input / Calc  Description/Calculated Variables / Options 
FOR EMBEDDED COOLING OPTION  
Cooler.On  tick box  Switches the cooler on/off 
Cooling.Type  Fixed.dQ  User specifies the energy change required. 
Fixed.dT  User specifies the temperature change required.  
HeatExchange  User specifies the HTC, Area and flow for heat exchange.  
Variables for the Fixed.dQ method  
dQ  Input  The user specified change of energy. 
Variables for the Fixed.dT method  
dT  Input  The user specified change of temperature. 
Variables for the HeatExchange method  
HX.Area  Input  The user specified heat transfer area. 
HX.HTC  Input  The user specified heat transfer coefficient. 
By.Vol.Flow  tick box  Slurry to "cooler" can be specified in mass or volumetric flows 
Heat Exchanger  
Cooling.MassFlow / Cooling.Qm  Input / Calc  The slurry mass flow to be cooled by the "cooler". Input allowed when By.Vol.Flow is not selected. 
Cooling.VolFlow / Cooling.Qv  Input / Calc  The slurry volumetric flow to be cooled by the "cooler". Input allowed when By.Vol.Flow is selected. 
Hx.UA  Calc  heat exchanger UA. 
Hx.LMTD  Calc  heat exchanger log mean temperature difference. 
Liquor.Tin  Calc  The slurry temperature into the "cooler". 
Liquor.Tout  Calc  The slurry temperature out of the "cooler". 
Coolant  
Water.Flow  Calc  Displays the CW mass flow into the "cooler" via the Cool_in connection. 
Water.Vol.Flow  Calc  Displays the CW volumetric flow into the "cooler" via the Cool_in connection. 
Water.Tin  Calc  Displays the CW temperature into the "cooler" via the Cool_in connection. 
Water.Tout  Calc  Displays the CW temperature out of the "cooler" via the Cool_out connection. 
Cooling.Rate  Calc  The rate of cooling. 
FOR EXTERNAL COOLING OPTION  
By.Vol.Flow  tick box  Slurry to "cooler" can be specified in mass or volumetric flows 
Ext.Cooling.VolFlow / Ext.Cooling.Qv  Input / Calc  Input or displays the mass flow into the external cooler via the Cool_in connection, depends on the By.Vol.Flow option. 
Ext.Cooling.MassFlow / Ext.Cooling.Qm  Input / Calc  Input or displays the mass flow into the external cooler via the Cool_in connection, depends on the By.Vol.Flow option. 
Ext.Cooling.Temperature / Ext.Cooling.T  Calc  The temperature of the "cooled" side stream returning to the precipitator. 
Ext.Cooling.TotHzOut  Calc  The total energy of the side stream leaving the precipitator. 
Ext.Cooling.TotHzIn  Calc  The total energy of the side stream returning to the precipitator. 
Cooling.Rate  Calc  The rate of cooling. 
PSD Tab
Only visible when Precip.Method = PSD. Please See Precipitation using Full PSD for more information on theory and method.
Tag (Long/Short)  Input / Calc  Description/Calculated Variables / Options 
PSDDefinition  List Box  Any predefined PSD definition in the project configuration file can be selected from this list. 
PSD Control  
Growth.On  Tick Box  Selecting this will enable growth rate calculation. Please see also Growth Rate Methods 
Agglom.On  Tick Box  Selecting this will enable agglomeration calculation. Please see also Implementation of a size dependent kernel 
Nucleation.On  Tick Box  Selecting this will enable nucleation rate calculation. [math]\displaystyle{ N = 5.0\times 10^8 \left(\frac{AA^*}C\right)^2\sigma }[/math] 
SodaWithNucleation  Tick Box  When this option is ticked, the bound soda calculations will be based on the total yield (growth + nucleation). If this is not ticked, the nucleation yield will be excluded in the bound soda calculations. 
NonPSDSolids  Tick Box  Selecting this will include Non THA Solids in PSD Mass 
AllSolidsDensity  Tick Box  Selecting this will include Non THA Solids in PSD Density 
SeedPSD  Tick Box  Selecting this will allow SysCAD to auto generate a small quantity of seed if NO THA solid was found in the Precipitation Feed. The generated amount will be sufficient to seed a tank and allow precipitation to occur in the tank. When solids returns to the tank via the proper seed streams, the recycled solids will take over and SysCAD will no longer generate any extra solids. See Using the Full PSD model. 
Area.Correction  Input  Scaling for nonsphericity. See Area Correction 
AcknowledgePSDOutletChange  Tick Box  Available from Build 139.30807. This checkbox will appear if the outlet Product stream had PSD action Create or Modify. Prior to this build, data from Create/Modify in the Product stream was able to affect the upstream unit model behaviour. Until this tickbox is checked to acknowledge the change, the model is unable to run. Model results will need to be reviewed and model may need to be retuned. 
PSD Display  
ShowRates  Tick Box  Selecting this will enable the display of Particle Size Number Data Table on the PSD tab. Please see Show Rates 
DisplayAsFraction  Tick Box  When this option is ticked, the rates (Growth, Agglom, etc.) are normalised by dividing by the particle numbers: that is, displayed as a fraction of the particle number. 
ShowAgglomKernel  Tick Box  Global option to show Kernel tab with agglomeration kernel beta terms. Note these values are the "raw kernel" before the inclusion of agglomeration rate or collision effects. 
TrackUltrafines  Tick Box  Warn if mass is present in smallest size bin  this is moved to next bin up. 
Agglomeration Parameters  
Agglom.UseMidSize  Tick Box  Use PSD interval mid size (geometric mean) (checked) or top size (unchecked) for Agglomeration Kernel calculations. Only applicable for some options of Agglom.Kernel.Type. 
Agglom.Kernel.Type  Size Independent  Ilievski size independent kernel (Light Metals, 1982). This assumes that all interactions are equally likely to cause an agglomeration event (i.e. beta = 1 for all size combinations). This option is typically paired with Agglom.Rate.Type Supersaturation. 
Ilievski  The kernel is of the form: [math]\displaystyle{ \frac {1}{D_{i}+D_{j}} }[/math]. See Size Dependent Kernel for more information. This option is typically paired with Agglom.Rate.Type of form Growth/Beta4. From Build 139, this is the default selection and [math]\displaystyle{ D_{i}+D_{j} }[/math] is replaced by [math]\displaystyle{ 2.\sqrt[m]{\frac{1}{2}(D_i^m+D_j^m)} }[/math], twice the Generalised Mean (see Wikipedia) of the interacting particle sizes with power [math]\displaystyle{ m }[/math] (Agglom.GenMeanPow). At default [math]\displaystyle{ m=1 }[/math] this is simply the sum.  
DavidRijkeboer  The kernel is of the form: [math]\displaystyle{ 1e9 \left( 1e9 \lambda_{trans}R_{L:T}\beta_{ij,L} + \left( 1  \lambda_{trans} \right) \beta_{ij,T} \right) }[/math]. See DavidRijkeboer Kernel for more information.  
User  This option allows manual input of the agglomeration kernel on the dKernel tab.  
Kernel Builder  Enables the Kernel Builder, available on the dKernel tab.  
Agglom.Rate.Type  Constant  The calculated agglomeration rate is set to 1, so in effect agglomeration rate is set directly using Agglom.Rate.Correction. This is equivalent to the option Agglom.RawKernel prior to Build 139. 
Supersaturation  The agglomeration rate is governed by a single equation dependant on temperature and liquor properties. Agglomeration rate is in the form: [math]\displaystyle{ 1.77\times 10^{4} \times \left(\frac{AA^*}C\right)^4 }[/math] . This option is typically paired with Agglom.Kernel.Type Size Independent.  
Growth/Beta4(T)  The agglomeration rate is of the form: [math]\displaystyle{ \frac {G^n}{\beta_4(T)} }[/math] where the calculated [math]\displaystyle{ \beta_4 }[/math] is a function of Temperature only. See Size Dependent Kernel for more information. This option is typically paired with Agglom.Kernel.Type Ilievski. From Build 139, this is the default selection.  
Growth/Beta4(T,Sh)  The agglomeration rate is of the form: [math]\displaystyle{ \frac {G^n}{\beta_4(T,Sh)} }[/math] where the calculated [math]\displaystyle{ \beta_4 }[/math] is a function of Temperature and Shear Rate. See Size Dependent Kernel for more information. This option is typically paired with Agglom.Kernel.Type Ilievski.  
Agglom.Collision.Type  RestrictedinSpace  This option assumes a particle can only interact with particles in its immediate vicinity, restricting the number of possible collisions. Applies a division by total particle count [math]\displaystyle{ N_T }[/math] . See FreeinSpace vs RestrictedinSpace. 
FreeinSpace  This option assumes the agglomeration rate is proportional to the total number of possible collisions between particles, any particle is free to collide with any other particle. Applies a division by 10^{9} (or 10^{12} prior to Build 139) to maintain a similar order of magnitude as RestrictedinSpace. See FreeinSpace vs RestrictedinSpace.  
Agglom.UseCorrectedCollision  Tick Box  Available from Build 139. (For backwards compatibility, may be visible if upgrading projects). Simplifies the FIS and RIS corrections, as described above. Recommend this box be checked and model retuned as necessary. 
Agglom.SolidsFracPow  Input  Power term for effect of solids volume fraction on agglomeration rate. Default 0. 
Agglom.GrowthRatePow  Input  Used with Agglom.Rate.Type of form Growth/Beta4. Power term for effect of growth rate on agglomeration rate. Default 1. 
Agglom.Cutoff  Tick Box  If selected, then particles greater than Agglom.Cutoff.Size will not agglomerate. 
Agglom.Cutoff.Size  Input  Maximum size for agglomerating particles. Only visible when Agglom.Cutoff is selected. 
Agglom.Cutoff.Used  Input  Actual size used for agglomerating particles. Only visible when Agglom.Cutoff is selected. 
Agglom.GenMeanPow  Input  Available with Agglom.Kernel.Type DavidRijkeboer and DavidRijkeboer. Power term for Generalised Mean of particle size interactions. Default 1 to give arithmetic mean (i.e. proportional to sum). For Agglom.Kernel.Type DavidRijkeboer this applies to the Laminar portion. 
Agglom.GenMeanPow2  Input  Available with Agglom.Kernel.Type DavidRijkeboer. As above. For Agglom.Kernel.Type DavidRijkeboer this applies to the Turbulent portion. 
Agglom.DR.MinSize  Input  Available with Agglom.Kernel.Type DavidRijkeboer. The Batchelor microscale, below which no agglomeration occurs. 
Agglom.DR.MaxSize  Input  Available with Agglom.Kernel.Type DavidRijkeboer. The Taylor microscale, above which no agglomeration occurs. 
Agglom.DR.TransSize  Input  Available with Agglom.Kernel.Type DavidRijkeboer. The Kolmogorov microscale, where agglomeration transitions from laminar to turbulent regime. 
Agglom.DR.TransSharp  Input  Available with Agglom.Kernel.Type DavidRijkeboer. Sharpness of the Kolmogorov transition. 
Agglom.DR.LTRatio  Input  Available with Agglom.Kernel.Type DavidRijkeboer. Multiplier to correct the order of magnitude of the laminar kernel before summation with the turbulent kernel. Internally, a hardcoded 1e9 is applied, such that this user input should be close to 1. 
Agglom.CalcBeta4  Tick Box  Used with Agglom.Rate.Type of form Growth/Beta4. Calculate (On) or user supplied (Off) [math]\displaystyle{ \beta_4 }[/math] in the Agglomeration Kernel equation. 
Agglom.UserBeta4  Input  Used with Agglom.Rate.Type of form Growth/Beta4. User specified [math]\displaystyle{ \beta_4 }[/math] for use in the Agglomeration Kernel equation. Only visible when Calc.Beta4 is not selected. 
Agglom.Beta4  Result  Used with Agglom.Rate.Type of form Growth/Beta4. [math]\displaystyle{ \beta_4 }[/math] in the Agglomeration Kernel equation. See Size Dependent Kernel 
Agglom.Rate.Magnitude  Input  Overall correction of magnitude for Agglomeration calculations *10^{n}. Default hidden, value 0. Used for coarse tuning only. 
Agglom.Rate.Correction  Input  Overall correction rate for Agglomeration calculations. 
Agglom.Rate.FineTuning  Input  Overall correction rate for Agglomeration calculations. Default hidden, value 1. Recommend to keep this term around 1.0 and use for localised finetuning. 
Nucleation Parameters  
Misra.Nucleation.Rate  Input  Nucleation Rate term, equivalent to [math]\displaystyle{ k \times e^{E/RT} }[/math]. See Nucleation 
Nucl.Rate.Correction  Input  Correction for Nucleation calculations 
Results  
Growth.Rate  Calc  Diametric (i.e. particle) growth rate. Same as GrowthRateD on the Precip tab. 
Agglom.Rate  Calc  The total agglomeration rate factor determined by the selection of Agglom.Rate.Type and Agglomeration.Collision.Type (and associated inputs) as well as Agglom.Rate.Magnitude and Agglom.Rate.Correction. This term is multiplied with the kernel and particle sizes at each particle size combination. See Model Theory  Agglomeration. 
Agglom.Degree  Calc  The degree of agglomeration at 45μm. Calculated as [math]\displaystyle{ \frac{[45μm]_{Feed} \quad  \; \; [45μm]_{Prod}} {[45μm]_{Feed}} }[/math] 
Nucleation.Rate  Calc  Net rate of increase in particle numbers due to nucleation. 
GrowthYield  Calc  The Growth Yield. Total new mass of THA in tank due to Growth. 
Nucleation.Yield  Calc  The Nucleation Yield. Total new mass of THA in tank due to Nucleation. 
NumMassIn  Calc  Mass of PSD Solids into the Precipitation Tank (Excludes NonPSD solids). 
NumMassOut  Calc  Mass of PSD Solids leaving the Precipitation Tank. 
Results (Particle Numbers)  
NumbersByMassIn  Calc  Number of particles per mass of slurry entering the Precipitation tank. 
NumbersByMassOut  Calc  Number of particles per mass of slurry leaving the Precipitation tank. 
NumbersByMassDelta  Calc  The number of particles generated in the Precipitation tank per mass of slurry in the tank. 
NumbersByVolIn  Calc  Number of particles per volume of slurry entering the Precipitation tank. 
NumbersByVolOut  Calc  Number of particles per volume of slurry leaving the Precipitation tank. 
NumbersByVolDelta  Calc  The number of particles generated in the Precipitation tank per volume of slurry in the tank. 
NumbersBySolidsOut  Calc  The number of particles generated in the Precipitation tank per mass of PSD solids in the tank. 
If ShowRates is selected, the following matrix of data with rates and numbers is shown:
Tag (Long/Short)  Description/Calculated Variables / Options 
Particle Size Numbers Data  
Particle Size Interval  Particle size interval as defined in the project configuration file. See Setting up the PSD Definition 
MidSize  [math]\displaystyle{ Geometric Mean_i = \sqrt{d_i * d_{i1}} }[/math], See Geometric Mean for more information. 
#/kg Sl in  Particle numbers in incoming slurry 
#/kg Sl tank  Particle numbers in the tank 
GrowthRate  Net rate of increase in numbers due to growth 
GrowthRate+  Rate of increase in numbers due to growth in from smaller bins 
GrowthRate  Rate of decrease due to growth out to larger bins. 
AgglomRate  Net rate of increase in numbers due to agglomeration 
AgglomRate+  Increase in numbers due to agglomeration from smaller bins 
AgglomRate  Decrease due to agglomeration to larger bins 
Tot.Rate  Agglom + Growth + Nucleation rates 
Rate*ResT  Tot.Rate times Residence Time. 
Ascending / Descending  Use the Ascending or Descending button to change the display order of the table. 
Notes:
 The model ignores particles in the smallest bin (passing the smallest size), and will never create particles in this size. The feed may have particles of this size if the PSD is created using e.g. the RosinRamler distribution. The TrackUltrafines option will warn when ultrafine particles are present, and move them to the next smallest bin.
dKernel and Kernel Tabs
Only visible when Precip.Method = PSD.
Kernel tab only shown when ShowAgglomKernel is selected. This shows the full array of [math]\displaystyle{ \beta }[/math] kernel values.
dKernel tab only shown when Agglom.Kernel.Type = User or Kernel Builder. With Agglom.Kernel.Type = User, [math]\displaystyle{ \beta }[/math] values are manually entered for the entire agglomeration kernel.
With Agglom.Kernel.Type = Kernel Builder, the following fields are available for building a custom kernel function. See Kernel Builder for more details.
Form of each term: [math]\displaystyle{ a.\left(\cfrac{f(L_i,L_j,[m])}{b}\right)^n+c }[/math]
Tag (Long/Short)  Input / Calc  Description / Calculated Variables / Options 
Kernel.Terms  Input  The number of terms in the agglomeration kernel calculation. 
Kernel.Factor  Input  Overall correction factor for the calculated agglomeration kernel. Typically used to correct magnitude. Note that this term is optional, and has the same effect as Agglom.Rate.Correction. 
The following are repeated for each Kernel.Terms. Note that Term# is replaced with Term1, Term2, etc.  
Kernel.Term#.Type Form of [math]\displaystyle{ f(L_i,L_j,[m]) }[/math] 
Sum  Sum of powers [math]\displaystyle{ L_i^m + L_j^m }[/math] 
Difference  Difference of powers [math]\displaystyle{ L_i^m  L_j^m }[/math]  
Product  Product [math]\displaystyle{ L_i.L_j }[/math]  
Maximum  Size of larger particle [math]\displaystyle{ L_i }[/math]  
Minimum  Size of smaller particle [math]\displaystyle{ L_j }[/math]  
Mean  Generalised mean [math]\displaystyle{ \sqrt[m]{\frac{1}{2}(L_i^m+L_j^m)} }[/math]  
Kernel.Term#.Power  Input  Overall power n. 
Kernel.Term#.PowerB  Input  Only available with Sum, Difference and Mean. Power on individual terms m. 
Kernel.Term#.Coefficient  Input  Coefficient a. 
Kernel.Term#.Divisor  Input  Divisor b. 
Kernel.Term#.Constant  Input  Constant c. 
Kernel.Term#.Denominator  Tick Box  Whether the term appears on the numerator (off) or denominator (on) of the kernel calculation. 
Classif Tab
Only visible when Classification tick box is selected. The full SolidLiquid Separator is used for General Separator and Evaporator, please see SolidLiquid Separator for more information on theory and method. The Classification sub model uses most of the solidliquid separator features. Difference and extra fields are documented here.
Tag (Long/Short)  Input / Calc  Description / Calculated Variables / Options 
Requirements  
SplitMethod  Solid Separation  This is the only available option as the embedded classifier will separate and recycle solids to meet target underflow solids concentration. 
Requirements (Solids / Liquids Separation) Please see Solid Separation for all Solid Separation Methods.  
The following is available when SolidsSeparaMethod = SolidsPSD.  
SolidMethod  Whiten  This method is based on a model proposed by Whiten. See Whiten for information. 
Karra  This method is based on a model proposed by V.K Karra and is only valid for screen cut apertures greater than 1mm. See Karra for information.  
RosinRammler  This method is based on a RosinRammler type of function with the efficiency curve expression derived by Reid and Plitt. See RosinRammler for information.  
Lynch  This method is based on a Lynch type of function. See Lynch for information.  
DelVillarFinch  This method includes a term for the "fish hook" effect for entrainment. See DelVillarFinch for information.  
Partition Curve  PartCrv Tab will open where user can define the Fraction of Feed Solids per size interval reporting to the oversize.  
Selected Solid Species Calculation Method
This section is used to set species Bypass options, (such as setting oxalate to bypass to O/F) , see Bypass Options for more information.  
Results  
Temperature  Calc  The temperature of the material leaving the classification section. 
MassFlow / Qm  Calc  The mass flow feeding the classification section, this includes the internal recycle. 
VapourMassFlow / VQm  Calc  The total flow of vapour to the Underflow and Overflow streams. 
UF.BypassMassFlow / UF.BypassQm  Calc  The mass flow of the material that bypasses the underflow. 
OF.BypassMassFlow / OF.BypassQm  Calc  The mass flow of the material that bypasses the overflow. 
BypassMassFlow / BypassQm  Calc  The mass flow of the solids in the unit that bypasses the separation section. 
UF.SolidsTakeoffQm  Calc  The internal solids recycle amount, displayed as solids mass flowrate. This is equivalent to the solids recycle stream on the Left image in Classification theory. 
UF.SolidsTakeoffFrac  Calc  The internal solids recycle amount, displayed percent solids recycled. This is equivalent to the solids recycle stream on the Left image in Classification theory. 
UF.FinalSolidFrac / UF.FinalSF  Calc  The final underflow solids fraction. This is after the recycle, thus the final underflow leaving the precipitation unit going forward. 
Separation Results  
UFSolidsRecovery  Calc  This is the internal classifier's underflow solids recovery, this is BEFORE the solids split to recycle. This is equivalent to the Classifier on the Left image in Classification theory. 
UFLiquidRecovery  Calc  This is the internal classifier's underflow liquid recovery, this is BEFORE the solids split to recycle. This is equivalent to the Classifier on the Left image in Classification theory. 
Content and Preset Tabs (Dynamic Only)
Content Tab: These displays the tank contents (total mass, volume, properties, etc.) in the standard Tank access window format.
Preset and DSp Tabs: allow the composition and contents to be preset.
Batch Tab (Probal Only)
Batch mode simulates a tank which is filled with separate PGL and Seed feed streams, allowed to precipitate, and then drained. In practice, a plant would have a number of tanks at different stages of the fill/precip/drain cycle, and the net operation is steady state; the contents of the product stream being determined by the composition at the end of batch cycle, and the flow rate determined by the total feed.
See Batch Mode for a more information.
Tag (Long/Short)  Input / Calc  Description/Calculated Variables / Options 
Batch Operating Parameters  
TankCount  Input  Number of Batch Tanks in the Precipitation bank (need not be integer) 
Level.SetPoint / Level.Spt  Input  Operating Level of Batch Tank 
PGL.VolFlowReqd / PGL.QvReqd  Input  PGL Fill Rate. The fill rate parameters can be different to actual PGL flow rates. If they are less, then we are filling multiple tanks simultaneously. If they are greater, then we are filling rapidly from a holding tank which is continuously filled from the feed streams. 
Seed.VolFlowReqd / Seed.QvReqd  Input  Seed Fill Rate. The fill rate parameters can be different to actual seed flow rates. If they are less, then we are seeding multiple tanks simultaneously. If they are greater, then we are filling rapidly from a holding tank which is continuously filled from the feed streams. 
Seed.Overlap  Input  Overlap of PGL and Seed. See Description of Batch Cycle for an illustration of fill time. 
Drawoff.VolFlowReqd / Drawoff.QvReqd  Input  Drawoff Rate. 
Drawoff.Overlap  Input  
MaxResidenceTime  Input  Maximum residence time in a batch tank. 
WaitTime  Input  After draining, there may be a specified wait time before filling starts again 
Feed Flow Conditions  
PGL.VolFlow / PGL.Qv  Result  Volume Flow of PGL. 
Seed.VolFlow / Seed.Qv  Result  Volume Flow of Seed. 
Calculated Cycle Times  
Seed.Time  Result  Total Time spent seeding. 
Drawoff.Time  Result  Total Time spent in drawoff. 
Recirc.Time  Result  Total Time spent in precipitation. 
AvailableCycleTime / Cycle.Time  Result  Overall Cycle Time. (Batch Cycle Done) 
Waypoints: PGL Filling starts at t=0  
PGL.EndTime  Result  PGL flow stopped. 
Seed.StartTime  Result  Seed flow started. 
Seed.EndTime  Result  Seed flow stopped. 
Drawoff.StartTime  Result  Drawoff started. 
Drawoff.EndTime  Result  Drawoff stopped. 
TankFlowTime  Result  Feed Time per tank. 
Levels during fill  
SeedEndFirst  Result  Returns true if the Seed period ends before PGL filling. 
Seed.StartLevel  Result  Level when seed started. 
PGL.EndLevel  Result  Level when PGL stopped. 
Seed.EndLevel  Result  Level when Seed stopped  generally equal to level setpoint. 
Tank Masses  
Seed.Mass / Seed.Mt  Result  Total Mass of Seed to tank. 
Seed.Volume / Seed.Vt  Result  Total volume of Seed to tank. 
Seed.SolidMass / Seed.SMt  Result  Total Solid Mass of Seed to tank. 
PGL.Mass / PGL.Mt  Result  Total Mass of PGL to tank. 
PGL.Volume / PGL.Vt  Result  Total volume of PGL to tank. 
Total.Mass / Total.Mt  Result  Total Mass of PGL and Seed to tank. 
Cooling  
MinLevel  Input  Level where cooling is started/stopped. 
Tank.VolFlow / Tank.Qv  Input  Flow of Cooling Water to Heat Exchange. This is the per tank cooling water flow. 
Total.VolFlow / Total.Qv  Result  The calculated cooling water flow is determined by the batch model and the specified per tank cooling water flow. For correct prediction of the cooling water return temperature, the actual cooling water flow should be set to this calculated number. See Cooling form more inforamtion. 
StartTime  Result  Cooling Initiated. 
EndTime  Result  Cooling Ended. 
Tank.TotalHeatXfer  Result  Batch Cycle Total Heat Transfer per Tank 
Tank.AverageHeatLoad  Result  Batch Cycle Average Cooling Load per tank 
Total.HeatLoad  Result  Total Cooling Load for all Tanks 
EHX  
Tank.TotalHeatXfer  Result  Batch Cycle Total Environmental Heat Loss per tank 
Tank.AverageHeatLoad  Result  Batch Cycle Average Environmental Heat Loss per tank 
Total.HeatLoad  Result  Total Environmental Heat Loss for all tanks. 
Batch Control  
Fill Steps  Input  Number of timesteps for fill. (Note: The default batch control parameters give sufficient accuracy for modelling.) 
Recirc Steps  Input  Number of timesteps for recircirculation. 
Drawoff Steps  Input  Number of timesteps for drawoff. 
Cycle Tab (Batch Mode)
Tag (Long/Short)  Row / Column Heading  Description 
Batch Data  
T1 to T65  Row Heading  Time segments during a batch cycle, for each time segment, the following data are displayed. 
Time / t  Col Heading  Time from start of filling 
AC  Col Heading  The ratio of A:C, where A is NaAl[OH]4 concentration, expressed as grams of Al2O3 /L liquor and C is Caustic concentration in NaOH + NaAl[OH]4, expressed as grams Na2CO3/L liquor. 
Solids  Col Heading  solids concentration. 
Temp / T  Col Heading  tank temperature 
Lvl  Col Heading  tank level 
HX  Col Heading  cooling heat transfer 
Rx  Col Heading  precipitation reaction heat 
EHX  Col Heading  environmental heat transfer 
SeedSol  Col Heading  seed solids flow 
PrecSol  Col Heading  solids precipitation 
PrecTHA  Col Heading  THA precipitation (excludes other solids) 
TotSol  Col Heading  tank solids content  cumulative seed + precipitated solids 
TotHt  Col Heading  total heat transfer (cooling + environmental heat transfer) 